File Handling in Python: Reading, Writing, and Managing Files with Examples

File Handling in Python

1. Basics of File Handling
Python uses the open() function to work with files. The syntax is:

file = open("filename", mode)

Modes for Opening Files:

Mode Description
r Read mode (default).
w Write mode. Overwrites if file exists.
a Append mode. Adds data to the end.
x Create mode. Fails if file exists.
b Binary mode.
t Text mode (default).


2. Reading Files
Reading the Entire File:

with open("example.txt", "r") as file:
content = file.read()
print(content)

Reading Line by Line:

with open("example.txt", "r") as file:
for line in file:
print(line.strip())

Reading Specific Number of Characters:

with open("example.txt", "r") as file:

, content = file.read(10) # Reads the first 10 characters
print(content)


3. Writing to Files
Writing a New File:

with open("output.txt", "w") as file:
file.write("This is a new file.\n")
file.write("File handling is easy in Python.")

Appending to a File:

with open("output.txt", "a") as file:
file.write("\nAdding another line.")


4. File Methods
Method Description
read() Reads the entire file content.
readline() Reads one line at a time.
readlines() Reads all lines and returns them as a list.
write() Writes a string to the file.
writelines() Writes a list of strings to the file.

Example:

lines = ["First line\n", "Second line\n", "Third line\n"]

with open("output.txt", "w") as file:
file.writelines(lines)


5. File Positioning
 Use the tell() method to get the current file position.